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Santiago Ramón y Cajal (May 1, 1852 – October 17, 1934) was a famous Spanish histologist, physician, and Nobel laureate, and is considered to be one of the founders of modern neuroscience. His most famous studies were on the fine structure of the central nervous system. Cajal used a histological staining technique developed by his contemporary, Camillo Golgi, allowing him to resolve, in detail, the structure of individual neurons. This led him to conclude that nervous tissue was a continuous reticulum (or web) of interconnected cells, much like those in the circulatory system. Using Golgi's method, Ramón y Cajal reached a very different conclusion; he postulated that the nervous system is made up of billions of separate neurons and that these cells are polarized. Rather than forming a continuous web, Cajal suggested that neurons communicate with each other via specialized junctions called "synapses". This hypothesis became the basis of the neuron doctrine, which states that the individual unit of the nervous system is a single neuron. Electron microscopy later showed that a plasma membrane completely enclosed each neuron, supporting Cajal's theory, and weakening Golgi's reticular theory.
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Science (from Latin scientia 'knowledge') is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe.
The earliest roots of science can be traced to Ancient Egypt and Mesopotamia in around 3000 to 1200 BCE. Their contributions to mathematics, astronomy, and medicine entered and shaped Greek natural philosophy of classical antiquity, whereby formal attempts were made to provide explanations of events in the physical world based on natural causes. After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages, but was preserved in the Muslim world during the Islamic Golden Age. The recovery and assimilation of Greek works and Islamic inquiries into Western Europe from the 10th to 13th century revived "natural philosophy", which was later transformed by the Scientific Revolution that began in the 16th century as new ideas and discoveries departed from previous Greek conceptions and traditions. The scientific method soon played a greater role in knowledge creation and it was not until the 19th century that many of the institutional and professional features of science began to take shape; along with the changing of "natural philosophy" to "natural science."
Modern science is typically divided into three major branches that consist of the natural sciences (e.g., biology, chemistry, and physics), which study nature in the broadest sense; the social sciences (e.g., economics, psychology, and sociology), which study individuals and societies; and the formal sciences (e.g., logic, mathematics, and theoretical computer science), which deal with symbols governed by rules. There is disagreement, however, on whether the formal sciences actually constitute a science as they do not rely on empirical evidence. Disciplines that use existing scientific knowledge for practical purposes, such as engineering and medicine, are described as applied sciences.
New knowledge in science is advanced by research from scientists who are motivated by curiosity about the world and a desire to solve problems. Contemporary scientific research is highly collaborative and is usually done by teams in academic and research institutions, government agencies, and companies. The practical impact of their work has led to the emergence of science policies that seek to influence the scientific enterprise by prioritizing the development of commercial products, armaments, health care, public infrastructure, and environmental protection. (Full article...)
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Featured articles are displayed here, which represent some of the best content on English Wikipedia.
The Hoxne Hoard (/ˈhɒksən/ HOK-sən) is the largest hoard of late Roman silver and gold discovered in Britain, and the largest collection of gold and silver coins of the fourth and fifth centuries found anywhere within the Roman Empire. It was found by Eric Lawes, a metal detectorist in the village of Hoxne in Suffolk, England in 1992. The hoard consists of 14,865 Roman gold, silver, and bronze coins and approximately 200 items of silver tableware and gold jewellery. The objects are now in the British Museum in London, where the most important pieces and a selection of the rest are on permanent display. In 1993, the Treasure Valuation Committee valued the hoard at £1.75 million (about £3.64 million in 2020).
The hoard was buried in an oak box or small chest filled with items in precious metal, sorted mostly by type, with some in smaller wooden boxes and others in bags or wrapped in fabric. Remnants of the chest and fittings, such as hinges and locks, were recovered in the excavation. The coins of the hoard date it after AD 407, which coincides with the end of Britain as a Roman province. The owners and reasons for burial of the hoard are unknown, but it was carefully packed and the contents appear consistent with what a single very wealthy family might have owned. It is likely that the hoard represents only a part of the wealth of its owner, given the lack of large silver serving vessels and of some of the most common types of jewellery. (Full article...)
Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. At room temperature and pressure, another solid form of carbon known as graphite is the chemically stable form of carbon, but diamond converts to it extremely slowly. Diamond has the highest hardness and thermal conductivity of any natural material, properties that are used in major industrial applications such as cutting and polishing tools. They are also the reason that diamond anvil cells can subject materials to pressures found deep in the Earth.
Because the arrangement of atoms in diamond is extremely rigid, few types of impurity can contaminate it (two exceptions are boron and nitrogen). Small numbers of defects or impurities (about one per million of lattice atoms) color diamond blue (boron), yellow (nitrogen), brown (defects), green (radiation exposure), purple, pink, orange, or red. Diamond also has a very high refractive index and a relatively high optical dispersion. (Full article...)
A tulip, known as "the Viceroy" (viseroij), displayed in the 1637 Dutch catalogue Verzameling van een Meenigte Tulipaanen. Its bulb was offered for sale for between 3,000 and 4,200 guilders (florins) depending on weight (gewooge). A skilled craftsworker at the time earned about 300 guilders a year.
Tulip mania (Dutch: tulpenmanie) was a period during the Dutch Golden Age when contract prices for some bulbs of the recently introduced and fashionable tulip reached extraordinarily high levels, with the major acceleration starting in 1634 and then dramatically collapsing in February 1637. It is generally considered to have been the first recorded speculative bubble or asset bubble in history. In many ways, the tulip mania was more of a then-unknown socio-economic phenomenon than a significant economic crisis. It had no critical influence on the prosperity of the Dutch Republic, which was one of the world's leading economic and financial powers in the 17th century, with the highest per capita income in the world from about 1600 to about 1720. The term "tulip mania" is now often used metaphorically to refer to any large economic bubble when asset prices deviate from intrinsic values.
Formal futures markets appeared in the Dutch Republic during the 17th century. Among the most notable centred on the tulip market, at the height of tulip mania. At the peak of tulip mania, in February 1637, some single tulip bulbs sold for more than 10 times the annual income of a skilled artisan. Research is difficult because of the limited economic data from the 1630s, much of which come from biased and speculative sources. Some modern economists have proposed rational explanations, rather than a speculative mania, for the rise and fall in prices. For example, other flowers, such as the hyacinth, also had high initial prices at the time of their introduction, which then fell as the plants were propagated. The high asset prices may also have been driven by expectations of a parliamentary decree that contracts could be voided for a small cost, thus lowering the risk to buyers. (Full article...)
Fertilisation of Orchids is a book by English naturalist Charles Darwin published on 15 May 1862 under the full explanatory title On the Various Contrivances by Which British and Foreign Orchids Are Fertilised by Insects, and On the Good Effects of Intercrossing. Darwin's previous book, On the Origin of Species, had briefly mentioned evolutionary interactions between insects and the plants they fertilised, and this new idea was explored in detail. Field studies and practical scientific investigations that were initially a recreation for Darwin—a relief from the drudgery of writing—developed into enjoyable and challenging experiments. Aided in his work by his family, friends, and a wide circle of correspondents across Britain and worldwide, Darwin tapped into the contemporary vogue for growing exotic orchids.
The book was his first detailed demonstration of the power of natural selection, and explained how complex ecological relationships resulted in the coevolution of orchids and insects. The view has been expressed that the book led directly or indirectly to all modern work on coevolution and the evolution of extreme specialisation. It influenced botanists, and revived interest in the neglected idea that insects played a part in pollinating flowers. It opened up the new study areas of pollination research and reproductive ecology, directly related to Darwin's ideas on evolution, and supported his view that natural selection led to a variety of forms through the important benefits achieved by cross-fertilisation. Although the general public showed less interest and sales of the book were low, it established Darwin as a leading botanist. Orchids was the first in a series of books on his innovative investigations into plants. (Full article...)
Cley Marshes is a 176-hectare (430-acre) nature reserve on the North Sea coast of England just outside the village of Cley next the Sea, Norfolk. A reserve since 1926, it is the oldest of the reserves belonging to the Norfolk Wildlife Trust (NWT), which is itself the oldest county Wildlife Trust in the United Kingdom. Cley Marshes protects an area of reed beds, freshwater marsh, pools and wet meadows and is part of the North Norfolk Coast Site of Special Scientific Interest (SSSI), Special Area of Conservation (SAC), Special Protection Area (SPA), and Ramsar Site due to the large numbers of birds it attracts.
The reserve is important for some scarce breeding species, such as pied avocets on the islands, and western marsh harriers, Eurasian bitterns and bearded reedlings in the reeds, and is also a major migration stopoff and wintering site. There are also several nationally or locally scarce invertebrates and plants specialised for this coastal habitat. It has five bird hides and an environmentally friendly visitor centre and further expansion is planned through the acquisition of neighbouring land and improvements to visitor facilities. (Full article...)- Debora Green (née Jones; born February 28, 1951) is an American physician who pleaded no contest to setting a 1995 fire which burned down her family's home and killed two of her children, and to poisoning her husband with ricin with the intention of causing his death. The case was sensational, and covered heavily by news media, especially in the Kansas–Missouri area, where the crimes occurred. Though Green has petitioned for a new trial twice in recent years, her requests have not been successful.
Green married Michael Farrar in 1979 while practicing as an emergency physician. The marriage was tumultuous, and Farrar filed for divorce in July 1995. Between August and September 1995, Farrar repeatedly fell violently ill, and despite numerous hospitalizations his doctors could not pinpoint the source of his illness. Green's emotional stability deteriorated and she began to drink heavily, even while supervising her children. On October 24, 1995, the Farrar family home, occupied by Green and the couple's three children, caught fire. Kate Farrar and Debora Green escaped without harm, but despite the efforts of firefighters, Timothy and Kelly Farrar died in the blaze. Investigation showed that trails of accelerant in the house led back to Green's bedroom, and that the source of Michael Farrar's intractable illness had been ricin, a poison served to him in his food by Green. (Full article...)
The splendid fairywren (Malurus splendens) is a passerine bird in the Australasian wren family, Maluridae. It is also known simply as the splendid wren or more colloquially in Western Australia as the blue wren. The splendid fairywren is found across much of the Australian continent from central-western New South Wales and southwestern Queensland over to coastal Western Australia. It inhabits predominantly arid and semi-arid regions. Exhibiting a high degree of sexual dimorphism, the male in breeding plumage is a small, long-tailed bird of predominantly bright blue and black colouration. Non-breeding males, females and juveniles are predominantly grey-brown in colour; this gave the early impression that males were polygamous as all dull-coloured birds were taken for females. It comprises several similar all-blue and black subspecies that were originally considered separate species.
Like other fairywrens, the splendid fairywren is notable for several peculiar behavioural characteristics; the birds are socially monogamous and sexually promiscuous, meaning that although they form pairs between one male and one female, each partner will mate with other individuals and even assist in raising the young from such trysts. Male wrens pluck pink or purple petals and display them to females as part of a courtship display. (Full article...)
Mounted skeleton cast, Senckenberg Museum of Natural History
Herrerasaurus was a genus of saurischian dinosaur from the Late Triassic period. This genus was one of the earliest dinosaurs from the fossil record. Its name means "Herrera's lizard", after the rancher who discovered the first specimen in 1958 in South America. All known fossils of this carnivore have been discovered in the Ischigualasto Formation of Carnian age (late Triassic according to the ICS, dated to 231.4 million years ago) in northwestern Argentina. The type species, Herrerasaurus ischigualastensis, was described by Osvaldo Reig in 1963 and is the only species assigned to the genus. Ischisaurus and Frenguellisaurus are synonyms.
For many years, the classification of Herrerasaurus was unclear because it was known from very fragmentary remains. It was hypothesized to be a basal theropod, a basal sauropodomorph, a basal saurischian, or not a dinosaur at all but another type of archosaur. However, with the discovery of an almost complete skeleton and skull in 1988, Herrerasaurus has been classified as an early saurischian in most of the phylogenies on the origin and early evolution of dinosaurs. (Full article...)
The killdeer (Charadrius vociferus) is a large plover found in the Americas. It was described and given its current scientific name in 1758 by Carl Linnaeus in the 10th edition of his Systema Naturae. Three subspecies are described. The killdeer's common name comes from its often-heard call. Its upperparts are mostly brown with rufous fringes, the head has patches of white and black, and two black bands cross the breast. The belly and the rest of the breast are white. The nominate (or originally described) subspecies breeds from southeastern Alaska and southern Canada to Mexico. It is seen year-round in the southern half of its breeding range; the subspecies C. v. ternominatus is probably resident in the West Indies, and C. v. peruvianus inhabits Peru and areas of the surrounding countries throughout the year. North American breeders winter from their resident range south to Central America, the West Indies, and the northernmost portions of South America.
The nonbreeding habitat of the killdeer includes coastal wetlands, beach habitats, and coastal fields. Its breeding grounds are generally open fields with short vegetation (but locations such as rooftops are sometimes used); although it is a shorebird, it does not necessarily nest close to water. The nest itself is a scrape lined with vegetation and white material, such as pebbles or seashell fragments. This bird lays a clutch of four to six buff to beige eggs with dark markings. The breeding season (starting with egg-laying) occurs from mid-March to August, with later timing of egg-laying in the northern portion of the range. Both parents incubate the eggs for 22 to 28 days typically. The young stay in the nest until the day after being hatched, when they are led by their parents to a feeding territory (generally with dense vegetation where hiding spots are abundant), where the chicks feed themselves. The young then fledge about 31 days after hatching, and breeding first occurs after one year of age. (Full article...)- Taare Zameen Par (transl. Stars on Earth), also known as Like Stars on Earth in English, is a 2007 Indian Hindi-language psychological drama film produced and directed by Aamir Khan. The film stars Khan himself, along with Darsheel Safary, Tanay Chheda, Sachet Engineer, Vipin Sharma and Tisca Chopra. The film explores the life and imagination of Ishaan (Safary), an 8-year-old dyslexic child. Although he excels in art, his poor academic performance leads his parents to send him to a boarding school. Ishaan's new art teacher Nikumbh suspects that he is dyslexic and helps him to overcome his reading disorder.
Creative director and writer Amole Gupte initially developed the idea with his wife Deepa Bhatia, who served as the film's editor. Shankar–Ehsaan–Loy composed the film's score, and Prasoon Joshi wrote the lyrics for many of the songs. Principal photography took place in Mumbai and in Panchgani's New Era High School, and some of the school's students make appearances. (Full article...) - In early philosophies of psychology and metaphysics, conatus (/koʊˈneɪtəs/; Latin for "effort; endeavor; impulse, inclination, tendency; undertaking; striving") is an innate inclination of a thing to continue to exist and enhance itself. This "thing" may be mind, matter, or a combination of both. Over the millennia, many different definitions and treatments have been formulated, including seventeenth-century philosophers René Descartes, Baruch Spinoza, Gottfried Leibniz, and Thomas Hobbes who had made significant contributions. The conatus may refer to the instinctive "will to live" of living organisms or to various metaphysical theories of motion and inertia. Often the concept is associated with God's will in a pantheist view of Nature. The concept may be broken up into separate definitions for the mind and body and split when discussing centrifugal force and inertia.
The history of the term conatus is that of a series of subtle tweaks in meaning and clarifications of scope developed over the course of two and a half millennia. Successive philosophers to adopt the term put their own personal twist on the concept, each developing the term differently. The earliest authors to discuss conatus wrote primarily in Latin, basing their usage on ancient Greek concepts. These thinkers therefore used "conatus" not only as a technical term but as a common word and in a general sense. In archaic texts, the more technical usage is difficult to discern from the more common one, and they are also hard to differentiate in translation. In English translations, the term is italicized when used in the technical sense or translated and followed by conatus in brackets. Today, conatus is rarely used in the technical sense, since modern physics uses concepts such as inertia and conservation of momentum that have superseded it. It has, however, been a notable influence on nineteenth- and twentieth-century thinkers such as Arthur Schopenhauer, Friedrich Nietzsche, and Louis Dumont. (Full article...) 
G. tibicen hypoleuca, Tasmania
The Australian magpie (Gymnorhina tibicen) is a medium-sized black and white passerine bird native to Australia and southern New Guinea. Although once considered to be three separate species, it is now considered to be one, with nine recognised subspecies. A member of the Artamidae, the Australian magpie is placed in its own genus Gymnorhina and is most closely related to the black butcherbird (Melloria quoyi). It is not, however, closely related to the European magpie, which is a corvid.
The adult Australian magpie is a fairly robust bird ranging from 37 to 43 cm (14.5 to 17 in) in length, with distinctive black and white plumage, gold brown eyes and a solid wedge-shaped bluish-white and black bill. The male and female are similar in appearance, and can be distinguished by differences in back markings. The male has pure white feathers on the back of the head and the female has white blending to grey feathers on the back of the head. With its long legs, the Australian magpie walks rather than waddles or hops and spends much time on the ground. (Full article...)
Quiriguá (Spanish pronunciation: [kiɾiˈɣwa]) is an ancient Maya archaeological site in the department of Izabal in south-eastern Guatemala. It is a medium-sized site covering approximately 3 square kilometres (1.2 sq mi) along the lower Motagua River, with the ceremonial center about 1 km (0.6 mi) from the north bank. During the Maya Classic Period (AD 200–900), Quiriguá was situated at the juncture of several important trade routes. The site was occupied by 200, construction on the acropolis had begun by about 550, and an explosion of grander construction started in the 8th century. All construction had halted by about 850, except for a brief period of reoccupation in the Early Postclassic (c. 900 – c. 1200). Quiriguá shares its architectural and sculptural styles with the nearby Classic Period city of Copán, with whose history it is closely entwined.
Quiriguá's rapid expansion in the 8th century was tied to king K'ak' Tiliw Chan Yopaat's military victory over Copán in 738. When the greatest king of Copán, Uaxaclajuun Ub'aah K'awiil or "18-Rabbit", was defeated, he was captured and then sacrificed in the Great Plaza at Quiriguá. Before this, Quiriguá had been a vassal state of Copán, but it maintained its independence afterwards. The ceremonial architecture at Quiriguá is quite modest, but the site's importance lies in its wealth of sculpture, including the tallest stone monumental sculpture ever erected in the New World. (Full article...)
Banksia epica is a shrub that grows on the south coast of Western Australia. A spreading bush with wedge-shaped serrated leaves and large creamy-yellow flower spikes, it grows up to 3½ metres (11½ ft) high. It is known only from two isolated populations in the remote southeast of the state, near the western edge of the Great Australian Bight. Both populations occur among coastal heath on cliff-top dunes of siliceous sand.
One of the most recently described Banksia species, it was probably seen by Edward John Eyre in 1841, but was not collected until 1973, and was only recognised as a distinct species in 1988. There has been very little research on the species since then, so knowledge of its ecology and cultivation potential is limited. It is placed in Banksia ser. Cyrtostylis, alongside its close relative, the well-known and widely cultivated B. media (southern plains banksia). (Full article...)
Commander Pete Conrad studies the Surveyor 3 spacecraft; the Apollo Lunar Module, Intrepid, can be seen in the top right of the picture.
Apollo 12 (November 14 – 24, 1969) was the sixth crewed flight in the United States Apollo program and the second to land on the Moon. It was launched on November 14, 1969, from the Kennedy Space Center, Florida. Commander Charles "Pete" Conrad and Lunar Module Pilot Alan L. Bean performed just over one day and seven hours of lunar surface activity while Command Module Pilot Richard F. Gordon remained in lunar orbit.
Apollo 12 would have attempted the first lunar landing had Apollo 11 failed, but after the success of Neil Armstrong's mission, Apollo 12 was postponed by two months, and other Apollo missions also put on a more relaxed schedule. More time was allotted for geologic training in preparation for Apollo 12 than for Apollo 11, Conrad and Bean making several geology field trips in preparation for their mission. Apollo 12's spacecraft and launch vehicle were almost identical to Apollo 11's. One addition was hammocks to allow Conrad and Bean to rest more comfortably on the Moon. (Full article...)
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The Milky Way is a barred spiral galaxy of the Local Group. Although the Milky Way is but one of billions of galaxies in the universe, the Galaxy has special significance to humanity as it is the home of the Solar System. The term "milky" originates from the hazy band of white light appearing across the celestial sphere visible from Earth, which is composed of stars and other material lying within the galactic plane. The fact that the Milky Way divides the night sky into two roughly equal hemispheres indicates that the solar system lies close to the galactic plane.
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More did you know...
- ...that a laser harp (pictured) is an electronic musical instrument consisting of several laser beams that are blocked to produce sound?
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